Intravascular treatment using a highly functional catheter, for example, such as a balloon catheter and a stent can be performed. In general, an imaging apparatus for diagnosis such as an optical coherence tomography (OCT) apparatus has been used for diagnosis before surgery or to confirm progress after surgery.
The optical coherence tomography apparatus incorporates an optical fiber, to which an imaging core having an optical lens and an optical mirror is attached to a distal end, and uses a probe of which at least a distal portion has a transparent sheath. The probe is guided into a blood vessel of a patient and radial scanning is performed by illuminating the blood vessel wall with light through the optical mirror while rotating the imaging core and by receiving reflected light from the blood vessel through the optical mirror again. A cross-sectional image of the blood vessel is constituted based on the obtained reflected light. Then, three-dimensional image of an inner wall of the blood vessel in a longitudinal direction is formed by performing a pulling operation (which is generally called pull-back) at a predetermined speed while rotating the optical fiber (JP-A-2007-267867). In addition, a swept-source optical coherence tomography (SS-OCT) apparatus using wavelength sweep has also been developed as a type of the OCT.